Creates a Discrete distribution which is uniform over values in
multiple ranges specified by pairs of start and end values. These pairs
are specified as adjacent values in an enumerable whose length must therefore be
even.

Creates a Discrete distribution which is uniform over values in
multiple ranges specified by pairs of start and end values. These pairs
are specified as adjacent values in an array whose length must therefore be
even.

The distribution is represented by a normalized Vector of length D.
In the case of a point mass, the first element is infinity and the second element holds the point location.
The probability of value x is available as this[x] or GetLogProb(x).